In conventional internal combustion engine carburetors, liquid fuel is aspirated into an airstream whereby small droplets of the fuel are entrained into the airstream during passage of the airstream from the carburetor to the cylinders of the internal combustion engine. The droplets are vaporized from the liquid state to the gaseous state and mixed with the air drawn through the carburetor. This mixture of vaporized fuel and air is then ignited within the cylinders of the internal combustion engine to provide power and movement to the engine.
As is well known in the art, carburetor devices of that nature are essentially compromises between efficiency and volumetric air/fuel throughputs of magnitudes great enough to provide sufficient power for high speed driving. While this comprise does allow operation of the internal combustion engine over wide ranges of speed and power requirements, the compromise also inherently provides for low effeiciency of carburetion of the fuel at certain operational speeds and for certain power requirements.
The art has long sought for modifications to conventional carburetors whereby increased efficiency of the internal combustion engine is obtained with subsequent further mixing and/or vaporization of the carbureted air/fuel mixture. Generally speaking, these efforts have centered around devices to be placed between the carburetor and the intake manifold to accomplish additional mixing and/or vaporization of the carbureted fuel prior to passage into the intake manifold. These devices have taken various forms in the prior art. For example, turbulence creating means and heat producing means have been placed between the carburetor and the intake manifold. Embodiments of the former include baffles, screens, perforated plates, tortuous paths created by metal turnings, foams, etc., and the latter of these includes hot exhaust gas injected into the air/fuel mixture, electrical heater elements disposed in the path of the air/fuel mixture, tubular heat exchangers through which the hot exhaust gas passes, and the like.
A difficulty often encountered by many of these devices is the lack of operational adjustability which will allow for different volumetric throughputs of carbureted air/fuel mixture, corresponding to different engine speeds and power requirements. For example, perforated plates and screen wires have constant openings thereof, and the volumetric throughput of the mixture which is occasioned by different engine speeds and power requirements does not create correspondingly different degrees of turbulence. Unfortunately, for increased efficiency, the turbulence created by the devices should be varied from low speeds and power requirements to higher speeds and power requirements, since the different degrees of turbulence are required to correctly augment the natural turbulence created by the carburetor which is greater at higher speeds than at lower speeds. The same is true for heater devices which function with exhaust gases. Thus, at higher speeds greater amounts of hot gases are available and at lower speeds lesser amounts of hot gases are available.
Of the prior art devices, one approach obviates the difficulties mentioned above. In this approach a rotatable turbulence producing means is placed between the carburetor and the intake manifold. While the turbulence producing means may take various forms, the general configuration thereof approximates the shape of a fan-type impeller. With this arrangement, the speed of rotation of the impeller, and hence the amount of the turbulence produced, is directly dependent upon the volumetric throughput of the carbureted air/fuel mixture. Thus, at higher speeds and at greater engine power requirements where the volumetric throughput is greater, the angular speed of rotation of the impeller is greater and, correspondingly, greater turbulence and mixing of air/fuel are provided. On the other hand, at lower speeds and engine power requirements, the volumetric throughput of the air/fuel mixture is less and, accordingly, the turbulence and mixing of air/fuel produced by the impeller are less. In other words, the rotatable impeller inherently adjusts in the speed of rotation whereby it corresponds to the engine speed and power requirements.
While the impeller device is, therefore, a preferred form of the turbulence producing devices, it also suffers from a decided disadvantage. This device is quite capable of intimately mixing already vaporized fuel with the carbureted air, and therefore increases the efficiency of the internal combustion engine, but the device is not capable of significantly vaporizing liquid fluel droplets aspirated into the air/fuel mixture during carburetion. These liquid droplets pass through the impeller device with, essentially, no more vaporization than is accomplished with the conventional carburetor. While the combintion of the impeller and a heat producing device, as described above, could be useful to both mix the fuel by action of the impeller and vaporize the droplets by action of the heat, known heat producing devices still suffer from being non-adjustable with engine speeds and power requirements as discussed above.
In view thereof, it would be desirable in the art to provide a means, in combintion with impeller mixing devices, which can increase the degree of vaporization of aspirated liquid fuel droplets. The increased vaporization along with the additional mixing of the vaporized fuel and air, occasioned by the impeller, would significantly increase the efficiency of the internal combustion engine.